Ethanol-amphetamine interaction effects on spontaneous motor activity and fixed-interval responding.
The spontaneous motor activity (SMA) of rats was recorded after injections of saline, d-amphetamine sulfate (0.8 mg/kg), and ethanol (400, 800, 1200, and 1600 mg/kg). Each drug treatment was given separately, and the amphetamine treatment was also combined with each ethanol dose. Ethanol, when injected without amphetamine, produced a dose-related decrement in SMA. Amphetamine, injected without ethanol, produced an increase in SMA. The combination of ethanol at 400 mg/kg with amphetamine potentiated the amphetamine-stimulant effect, but higher doses of ethanol counteracted amphetamine-produced increment in SMA. In a second experiment, similar combinations of ethanol and amphetamine were administered to rats lever-pressing for food pellets under a fixed-interval reinforcement schedule. The effect of amphetamine alone depended on baseline rate and varied among individual rats. Ethanol had a depressant effect on response rates, but combinations of the two drug treatments produced rates that, in most rats, were higher than after any single drug or saline treatment.
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects*; D051381:Rats; D012055:Reinforcement Schedule
D000431:Ethanol; D003913:Dextroamphetamine